Organic-inorganic lead halide hybrids have appealed great interests in solid-state lighting, due to their high absorption coefficients, superior color tunability and low-cost solution processing. However, rational design of bulk lead halide hybrids with high efficiency photoluminescence remains a challenge.

Heterometallic bulk luminophors, which show excellent structural designability and highly sensitized photoluminescence stemming from the strong coupling of different metal centers, provide new insights into the exploration of lead-halogen hybrids with highly efficient photoluminescence.

In a study published in J. Am. Chem. Soc., a research group led by Prof. LUO Junhua from Fujian Institute of Research on the Structure of Matter (FJIRSM) of the Chinese Academy of Sciences developed an unprecedented two dimensional (2D) Pb-Mn heterometallic halide hybrid through a precisely tailored synthetic approach. 

The researchers revealed that the unique two-dimensional heterometallic halide [Pb₄MnCl₁₄]_∞ nets are linked by PbMnCl₉ dimer clusters and Pb₃Cl₁₄ trimer clusters.

The Pb-Mn heterometallic halide hybrid exhibited a highly enhanced photoluminescence quantum efficiency (PLQE) up to 32%, considerably higher than that of pristine one (less than 1%). This strong emission is ascribed to the internal ⁴T₁ → ⁶A₁ transition of Mn²⁺, sensitized by the efficient energy transfer from the excitons to Mn²⁺ in the confined heterometallic halide layered structure.

In addition, they found that the prominent environmental and thermal stability benefits from the clusters feature.

This 2D Pb-Mn heterometallic halide hybrid with highly sensitized Mn²⁺ emission is unprecedented, which opens up a new route towards superior light emitters via sensitization in rationally designed heterometallic halide hybrids.

Schematic illustration of the strategy (Image by Prof. LUO’s group)